#!/usr/bin/env node
var pi=Math.PI;
class Circle{
  constructor(radius){
this.r=radius
  }
  diameter=function(){
    return 2*this.r;
  },
    circumference=function(){
      return 2*pi*this.r;
    },
    area=function(){
      return pi*this.r*this.r;
    }
};
module.export=Circle;
